The present invention is related to damping apparatus for use with bicycle forks, and more particularly, to damping apparatus of the type that provides fluid damping.
Conventional bicycle forks connect a front wheel of a bicycle to a bicycle frame so that the rider can rotate the front wheel and steer the bicycle. The bicycle fork typically includes a fork steerer tube that is easily rotated by handlebars. The steerer tube is coupled to a fork crown that extends across the top of the bicycle wheel. Two blades extend from opposing ends of the fork crown on opposite sides of the wheel to securely attach the crown to opposite sides of an axle of the front bicycle wheel.
Bicycle forks are not only used to steer bicycles, but they are also used to absorb various loads that are experienced by the front wheel of such bicycles. These conventional bicycle forks are known to include inner and outer telescoping members that are compressible toward one another and expandable away from one another to absorb shock.
In rough terrain, however, these telescoping bicycle forks often rebound too rapidly after hitting a large bump. Some bicycle riders have also found that traditional telescoping bicycle forks compress too rapidly upon hitting bumps. Therefore, manufacturers of bicycle forks have developed damping apparatuses that have damping mechanisms for controlling the relative movement between the telescoping members.
Although bicycle riders have embraced damping bicycle forks, as riders maneuver their bicycles over rougher terrain for longer lengths of time heat, build-up within the damping fluid can cause some traditional forks to xe2x80x9cseizexe2x80x9d due to pressure buildup from the fluid expanding in a closed system. It would, thus, be desirable to provide a damping apparatus for forks that allows for the fluid to expand while being pressurized. In addition, it is commonly known in the art that weight is an undesirable factor in bicycle design. Accordingly, it would be further desirable to provide such a damping system that is not complex and does not add unnecessary weight to the bicycle.
An illustrative embodiment of a bicycle fork provides a damping apparatus comprising a cylinder, a fluid, and a floating piston. The cylinder includes a fluid chamber with the fluid located within the fluid chamber. The floating piston is coupled to the cylinder and is configured to carry the fluid in the fluid chamber. The floating piston is also configured to be movable in response to movement of the fluid when a force is applied to the cylinder. Further embodiments of the damping apparatus may include the floating piston defining one end of the fluid chamber. The cylinder may provide a second chamber adjacent the fluid chamber and be separated from the fluid chamber by the floating piston. A member may be included that is disposed in the cylinder and is configured to displace fluid. The displacement biases the fluid against the floating piston. A bias member may be included to bias the floating piston against of fluid.
Another illustrative embodiment of the bicycle fork provides a damping apparatus further comprising a second piston. The second piston is disposed in the fluid chamber and is movable relative to the cylinder. Additional illustrative embodiments include a second cylinder configured to telescopically receive the first cylinder.
Another illustrative embodiment of the bicycle fork comprises a crown member, a first leg and a second leg. The first leg depends from the crown member and comprises a damping apparatus. The damping apparatus comprises a cylinder having a fluid chamber, a fluid located within the fluid chamber, and a floating piston coupled to the cylinder. The floating piston is configured to carry the fluid in the fluid chamber, and is configured to be movable in response to movement of the fluid when an external force is applied to the cylinder. The second leg also depends from the crown member and is spaced apart from the first leg. The second leg includes a spring apparatus comprising a second cylinder and a spring disposed in the second cylinder. The spring is configured to compress in response to the external force applied to the second cylinder.
Another illustrative embodiment of the damping apparatus comprises a cylinder, a piston, a fluid, and a resilient member. The cylinder is defined by a longitudinally-extending inner wall and comprises coaxially-aligned first and second fluid chambers that are disposed within the cylinder. The piston is disposed within the cylinder to separate the first and second fluid chambers. The piston also comprises at least one aperture disposed therethrough to allow communication between the chambers. The fluid is located within both the first and second chambers. The resilient member is located within the second chamber adjacent the inner wall, as well as located between the inner wall and a volume of the fluid. As a shock force is applied longitudinally against the cylinder, the fluid in the second chamber is caused to apply a lateral force against the resilient member. This force compresses the resilient member against the inner wall to allow an increase in volume of the fluid that occupies the second chamber.
Additional features and advantages of the apparatus will become apparent to those skilled in the art upon consideration of the following detailed descriptions exemplifying the best mode of carrying out the apparatus as presently perceived.